Process of forming aeroplane structural elements.



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PIBDCESS 0F FORMING AEBOPLAN E STRUCTURAL ELEMENTS.

1,269,420. In Drawing.

To all whom it may concern:

Be it known that I, WILLIS A. GIBBONB, a citizen of the United States, residing at Flushing, L. 1., county of Queens, and State of New York, have invented certain new and useful Improvements in the Processes of Forming Aeroplane Structural Elements, of which the following is a full, clear, and exact description.

This invention relates to processes of manufacturing aeroplane structural elements embodying a hard rubber containing sheet, and has for an object to provide a process for more smoothly and more effectively applying a sheet of this character to its supporting frame than has hitherto been possi le.

Hard rubber treated fabric is particularly adapted for use in the manufacture of aeroplane structural parts such as wings, pontoons, etc., on account of ossessing very little stretch, considerable stlfl'ness, and being unaffected by weather conditions. However difiiculty has been experienced in accurately shaping this material to the contour of a Wing frame or other supporting frame, on account of the material having so little stretch at atmospheric temperature that it resists distortionand has a tendency to maintain a fiat or plane condition. Furthermore in the construction of wings particularly, it is desirable that the sheet exert a tension on the frame to enhance the rigidity of the unit, but hitherto the hard rubber sheet has not accomplished this on account of its resistance to being tensioned.'

The present invention obviates the above diliiculties by heating the sheet to give the hard rubber greater extensibility, and stretching taut and securing the heated sheet to the frame under tension. While cooling, the sheet shrinks and assumes perfectly the contour of its suporting frame, and at the same time supplies the desirable tension to the frame.

In carrying out the invention, I have found it desirable to heat the sheet at localized portions after it has been fastened to the'supporting frame by some temporary means such as tacks. I have found it practical to carry out the heating step by first stretching the sheet as much as possible, lightly tacking it to the frame, and then warming with a flat iron. After each por- Specification 0! Letters Patent.

Patented June 11, 1918.

Application filed September 25, 1816. Serial No; 122,189.

tion is warmed, the tacks are removed, tension is applied to the warmed area from the edges of the sheet, and then while held taut under tension the heated portion is retacked to the frame. Then the next contiguous portion is treated in like maner, and the operation is continued progressively until the tensioned sheet is completely fastened to tic, the rubber treated sheet then having a degree of extensibility a proximately equal to that of untreated fabric. In this condition the sheet can be drawn tightly to conform perfectly to the contour of the sup orting means, such as the ribs of a wing rame. When permanently fastened and allowed to cool the rubber regains its original stiffness and at the same timeshrin producing a still greater degreeof tautness, thus supplying the desirable tension to the frame.

It is of course; not mat-swim tofasten the fabric before heating. the temporary fastening may be dispensed with. likewise it is not essential to heat locally. The entire surface may be warmed simultaneously. Also the heat may be applied by any suitable method.

Having thus described my invention, What I claim aS new and desire to protect by Letters Patent is:

1. The process of forming aeroplane structural elements consisting of heating a hard rubber treated sheet to give it greater extensibility, while warm stretching the sheet taut, securin the taut sheet to a supporting frame, and shrink.

2. The process of forming aeroplane structural elements consisting of temporarily applying to a frame a sheet of fabric treated with hard rubber, to give the rubber greater extensibility, While warm stretchingthe sheet taut, securing the taut sheet to the frame, and permitting the sheet to shrink.

3. The process of forming aeroplane 110 permitting the sheet to heating the sheet in usage wings, consisting of heating a hard rubber containing sheet to give it greater extensibility, stretching and securing the heated sheet to a wing frame, and permitting the sheet'to shrink.

4. The process of formin the frame under tension, and permittin the sheet to shrink. V 6. An aeroplane structural element comprising a frame, and a hard rubber treated sheet shrunk on and supplying tension to the frame. 4

I. An'aeroplane structural element com 25 prising a frame, and a hard rubber treated sheet of fabric shrunk on and supplying tension to the frame. i I

8. An aeroplane wingmor the like comaero lane wings, consisting of temporari y app yingto a win frame a sheet of fabric treated with har rubber, heating the sheet to give it greater extensibility, stretehin the heated sheet, securing the sheet to the ame under tension, and permitting the sheet to shrink.- --pris' a frame, and 'a rd rubber treated 30 5. The process of forming aeroplane I sheet of fabric shrunk on and supplying wings, consisting of temporari fastenitngfi tension to the frame. to the winghframe a sheetof fa ric trea Signed at New York, count and State with hard rubber, p'rogressiyely heating the of New York, this 13th day 0 September sheet at localized portions, stretching the 1916. p

WILLIS A. GIBBONS.

portions heated, securing said portions to 

